A long-simmering dispute over a string of islands in the East China Sea heats up after the collision of a Chinese trawler with Japanese patrol ships. Experts say long-term relations between the nations could suffer.The arrest of a Chinese fishing boat captain by Japan this week has worsened a historical rift between Tokyo and Beijing over a string of disputed islands in the East China Sea that could threaten long-term relations between the two Asian neighbors, experts warned Friday.